The Exploration And Application Of Biological Materials In Cardiovascular Diseases

【Objective】A bi-layered small-caliber vascular scaffold with outstanding mechanical properties and good cell adhesion was prepared based on artificial polymer material PLCL and natural material SF,and its application prospect was preliminarily evaluated.Besides,we designed and applied a novel Glenn fenestration to reduce the difficulty of the second stage of intervention in Hybrid Fontan surgery by reserving different fenestrations in the center of the two Gore-Tex patches.【Methods】The traditional electrospinning technique was used to design a two-step electrospinning method.The inner layer of the artificial vascular scaffold was prepared by coaxial electrospinning--a dense PLCL/SF/Hep nanofiber layer,and the outer layer of artificial vascular scaffold was prepared by conjugate electrospinning–a loose PLCL/SF nano-yarn layer.Then,the morphology,mechanical test,hydrophilicity evaluation,blood compatibility and cell compatibility evaluation of bi-layered artificial vascular scaffold were performed in vitro.Finally,perform orthotopically transplantation of the unilateral common carotid artery of New Zealand White Rabbits.Vascular ultrasound was performed regularly to evaluate the vascular patency.The venous blood immunoglobulin level was collected 3days after surgery to evaluate the rejection of the material.Post-operatively,HE staining,CD31 andα-SMA immunofluorescence staining were used to evaluate cell adhesion.Through the right atrial（RA）incision,two Gore-Tex patches with different fenestrations in the middle were sewn in the RA to“close”the superior vena cava（SVC）-RA junction and RA-inferior vena cava（IVC）junction.The fenestration of the SVC-RA patch played a role in decompression of SVC to reduce the pressure of central venous pressure（CVP）.Meanwhile,it could be an entrance for stent placement,avoiding needle acupuncture and laser burning.The fenestration of the RA-IVC patch not only introduced the blood flow from the IVC into the RA,but also supported the fixation of the stent.【Results】The bi-layered small-caliber vascular scaffolds based on PLCL/SF had good morphology,dense inner layer and loose outer layer.The mechanical properties met the application requirements.The hydrophilicity of the material was prominent,which was beneficial to the adhesion of endothelial cells and smooth muscle cells in the blood flow environment.Blood compatibility and cytocompatibility showed that the material owned good biological properties and had a positive effect on anti-platelet aggregation and promoting cell adhesion and proliferation.Ultrasound evaluation showed that the bi-layered vascular scaffolds remained patency after 3 months of orthotopic transplantation of rabbit unilateral carotid artery.The blood inflammation index did not indicate the rejection of the organism.The cell-specific staining showed that the vascular inner layer was neo-intimalized（good re-endothelialization and proliferation of smooth muscle cells）.During the hospitalization,the postoperative blood oxygen saturation（Sa O₂）of both children maintained above 85%and the CVP remained at 15mm Hg and 14mm Hg,respectively.Long-term follow-up after discharge,these two children were with a good quality of life.【Conclusion】Combining the excellent mechanical properties of the polymer with the outstanding hydrophilicity of the natural material,the bi-layered small-caliber artificial vascular scaffolds based on PLCL/SF has a good patency rate after the transplantation and can spontaneously adhere to the endothelium cells and smooth muscle cells in the blood flow environment,finally inducing vascular remodeling regeneration.We modified the traditional Glenn treatment.It is suitable for some favorable patients especially for those with high CVP and can reduce the technical threshold of the intervention.